<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<meta http-equiv="X-UA-Compatible" content="IE=edge">
		<title>使用less自动进行移动端rem适配计算</title>
		<meta name="viewport" content="width=device-width, initial-scale=1">
		<link rel="stylesheet/less" type="text/css" href="less/rem.less">
		<script src="js/less.js"></script>
	</head>
	<body>
		<div class="content">susu小苏苏</div>
	</body>
	<script>
		// JavaScript Document
		(function flexible(window, document) {
			var docEl = document.documentElement; //获取文档根节点并保存到变量docEl中(相当于获取到html对象)
			var dpr = window.devicePixelRatio ||
			1; //获取像素比，如果window.devicePixelRatio为false是dpr为1，如果window.devicePixelRatio大于1，那么dpr赋值取大的数

			function setBodyFontSize() {
				if (document.body) { //获取到body对象是否存在，个人觉得啰嗦
					document.body.style.fontSize = (12 * dpr) + 'px';
				} else {
					document.addEventListener('DOMContentLoaded', setBodyFontSize);
				}
			}
			setBodyFontSize();

			// set 1rem = viewWidth / 10
			function setRemUnit() {
				var rem = docEl.clientWidth / 10
				docEl.style.fontSize = rem + 'px'
			}

			setRemUnit()

			// reset rem unit on page resize
			window.addEventListener('resize', setRemUnit)
			window.addEventListener('pageshow', function(e) {
				if (e.persisted) {
					setRemUnit()
				}
			})

			// detect 0.5px supports
			if (dpr >= 2) {
				var fakeBody = document.createElement('body')
				var testElement = document.createElement('div')
				testElement.style.border = '.5px solid transparent'
				fakeBody.appendChild(testElement)
				docEl.appendChild(fakeBody)
				if (testElement.offsetHeight === 1) {
					docEl.classList.add('hairlines')
				}
				docEl.removeChild(fakeBody)
			}
		}(window, document))
	</script>
</html>
